Radiographic opaque and conductive striped medical tubes

ABSTRACT

A catheter or other medical tube is formed by extruding of a suitable thermoplastic with an integral stripe portion simultaneously formed by extruding of the same or a compatible plastic material into the wall of the tube. The integral stripe portion has dispersed therein a powdered conducting metal or carbon and an X-ray opaque powdered salt such as a bismuth or bromide salt. The completely different functioning pigments may be incorporated in sufficient quantities to provide reliable dual functions without disrupting or otherwise adversely affecting the strength and characteristic of the tube for the purposes intended in the medical art. The stripe portion is preferably crowned to extend the exterior surface from the contiguous body of the tube and thus further provide additional carrier for the mixture of the two different pigments. The conductive pigment is also partially opaque and thus generally a mixture of 85% conductive pigment and 15% X-ray opaque pigment produces an exceptionally satisfactory construction. The integrated dual functioning stripe portion produces a single medical tube creating the advantages of the individual tubes heretofor provided in the art and thus usable in widely varying applications.

This is a divisional application of application Ser. No. 634,075, filedNov. 21, 1975, now U.S. Pat. No. 4,027,659.

BACKGROUND OF THE INVENTION

This invention relates to a radiographic opaque and conductive stripedmedical tube such as catheters, cannulae and other similar tubes whichare introduced into the body cavity during medical procedures and inparticular to such a tube which can be accurately located throughradiographic observation and which eliminate possible hazardouselectrostatic charge conditions.

Catheters and like cylindrical tubes for introduction to the body cavityare presently of rubber, vinyl and other thermoplastic materials.Extruded plastic materials are widely employed because of the economiesof production which permit construction of disposable tubes. Such tubeshave been constructed with an X-ray opaque stripe extending throughoutthe length of the tube. By directing a beam of X-rays through the bodyof the patient in the neighborhood of the inserted medical tube, therelative position of the catheter and the living tissue will appear on afluoroscope or X-ray film. The stripe may include any suitable X-rayopaque pigment such as one of the bismuth salts. A highly satisfactoryX-ray opaque medical tube is more fully disclosed in U.S. Pat. No.3,749,134 wherein the tube is formed of suitable thermoplastic resinincluding a particular diol of a tetrabromophthalic anhydride to makethe tube radiographic. In addition to location of the tube within thebody cavity, care must often be taken such as under surgical proceduresto avoid creation of electrostatic discharge conditions. Thus, plasticmaterials which are widely employed in surgical tubes are known toacquire electrostatic charges when brought in frictional contact withother bodies such as certain fabrics. This may create a highly hazardouscondition in the presence of explosive gases such as will normally beencountered in surgical areas as a result of the use of variousanesthetizing gases. Recommended safe-practice standards have beenestablished requiring the use of electrically conductive elements withinthe tube to permit grounding and discharge of any electrostatic charge.It has even been suggested that the tube be formed with a suitableconductive strip formed by conductive particles dispersed throughout thestrip portion of the tube. When using a pigment, consideration must begiven to the strength characteristics of the tube and the like. Further,as the particles are completely of different characteristics andfunction in completely different manners, individual and separatestripes have been employed. The formation of a tube with the severaldifferent stripes and characteristics presents significant practicaldifficulties in the construction of a tube and generally the tubes haveheretofor been constructed with either one or the other of theindividual and separate functional portions.

SUMMARY OF PRESENT INVENTION

The present invention is particularly directed to medical tubes formedof a suitable flexible material and including an integral stripe portioncontaining a mixture of a highly conductive first material and aradiographic opaque second material intimately mixed and dispersed inthe single stripe portion, whereby said single stripe portion is bothoperable for grounding of the tube and for radiographic observation ofthe tube's position. Generally, in accordance with the presentinvention, the medical tube is formed by extruding of a suitable plasticmaterial or the like with the stripe portion simultaneously formed byextruding of the same or a compatible plastic material into the wall toform the separate but integral stripe portion which has dispersedtherein the first and second materials and thereby form a single, fusedlongitudinally extending stripe portion within the tube. The twomaterials may be suitable pigments such as a powdered conducting metalor carbon, and an opaque powdered salt such as a bismuth or bromidesalt. The inventor has found that the completely different functioningmaterials can be incorporated into the single stripe in sufficientquantities to provide reliable dual functions and with each materialfunctioning without interfering with the functioning of the oppositematerial. The single stripe can be formed with a sufficient density ineach of the integral materials without in fact disrupting or otherwiseadversely affecting the strength and characteristic of the tube for thepurposes intended in the medical art. The portion can be formed with acrown to extend the exterior surface from the contiguous body of thetube and thus further provide the desired carrier for the mixture of thetwo different pigments. Consequently, the integrated dual functioningstripe produces a single medical tube creating the advantages of theindividual tubes heretofor provided in the art and thus usable in widelyvarying applications.

The present invention thus provides an improved universal medical tubeand method of forming such a universal medical tube which can be carriedout with conventional processing equipment so as to produce aninexpensive, reliable and high quality medical tube.

BRIEF DESCRIPTION OF THE DRAWING

In the drawing:

FIG. 1 is a plan view of a fragmentary portion of a surgical tubeconstructed in accordance with the teaching of the present invention;and

FIG. 2 is an enlarged section, transverse section taken along line 2--2of FIG. 1.

DESCRIPTION OF ILLUSTRATED EMBODIMENT

Referring to the drawing, a medical tube 1 is illustrated including atubular portion 2 within which an unique stripe portion 3, constructedin accordance with the present invention, is integrally formed andextending through the complete length thereof.

The tube body 2 and the stripe portion are formed of a suitable flexibleplastic medium, such as a thermoplastic resin including polyethylene,vinyl polymers, and the like, as more fully discussed in the inventor'sissued U.S. Pat. No. 3,749,134. The body portion 2 may be formed as aclear transparent portion for convenient visual inspection or mayinclude a suitable dye to tint the tube while permitting inspection. Thestripe portion 3 is preferably formed of the same plastic base materialbut may of course be any other suitable base material which iscohesively compatible with that of the tube 2 to form a single integralmember.

In accordance with this invention, the base or carrier material 4 of thestripe portion 3 includes first and second particles or pigments 5 and6. The first pigment 5 is a highly conductive material such as anysuitable metal or other solid conductive particles which can be formedas very finely divided particles or powder. Generally, an electricallyconductive carbon, which is readily available as a standard commercialproduct in powdered form is preferably employed because of its stablecharacteristic as well as good conductivity. The dispersing of thecarbon pigment 5 throughout the tube portion 3 establishes anelectrically conductive path. In use, the proximal end of the tubeportion 3 is connected to a ground as shown diagrammatically at 7. Anysuitable well known connector, not shown, can of course be employed. Thegrounded conductive path prevents the build up of an electrostaticcharge, or retention of any previous charge, and the tube 1 maytherefore be safely employed in surgical procedures and the like. Thesecond pigment 6 is a suitable finely divided powder of a radio-opaquematerial such as the well known bismuth salts or, as disclosed in theinventor's U.S. Pat. No. 3,749,134, a bromide salt. These pigments arealso readily available in commerce in finely divided powdered form andthus may be conveniently mixed with the conducting pigment 5.

In making of the unique radiographic opaque and conductive striped tube,conventional multiple orifice extrusion equipment can be employed. Insuch devices, the main visible body, portion 2 of the tube 1 is extrudedthrough a major orifice of an extrusion die and simultaneously thelongitudinally extending striped portion 3 is extruded through a minororifice or orifices of the extrusion die. By the use of the same orcompatible plastic materials in the body portion 2 and as the carrier 4in the stripe portion 3, a single integral tube results with the dualfunctioning stripe formed therein.

Although the percentages of pigment loading are not critical, Applicanthas generally found that it is advisable to maintain the total pigmentloading of the tube stripe portion 3 below 70% (percent) by weight ofthe thermoplastic resin composition including the resin and plasticizersemployed and preferably within the range of 15 to 40% by weight of suchof the thermoplastic resin composition. Generally, the materials may beconveniently constructed with the conductive material 5 forming 85% ofthe total volume of added pigment and the radio-opaque material 6constituting the other 15 percentage of the total added pigment. Theratio is not critical and may be varied to employ equal amounts ofpigment. Generally, the conductive material particularly if a conductivecarbon is employed predominates to insure good conductivity. Althoughnot a conventional X-ray opaque material, the inventor has found that itdoes in fact produce some visual imaging and when combined with evenrelatively low proportions of X-ray opaque material produces a highlysatisfactory dual functioning stripe portion.

The inventor has also found that the tube 1 is also advantageouslyformed with the exterior wall 8 of the stripe portion 3 protrudingoutwardly of the contiguous outer wall 9 of the body portion 2 of thetube 1, as most clearly shown in FIG. 2. This permits the somewhatgreater volume of plastic carrier into which the two different pigmentscan be distributed. Thus the loading of the relatively thin body portionof the tube can be somewhat reduced, thereby insuring desirable strengthcharacteristics and the like of the medical tube 1. The protrudingportion is preferable formed as a crowned protruding configuration todefine a smooth, continuous exterior surface.

The inventor has found that the incorporation of the two differentmaterials in a common stripe portion can be readily provided without inany way adversely affecting the characteristic of the tube for theintended purposes and/or interfering with the complete reliablefunctioning of the X-ray transparent conductive material 5 and thenon-conductive X-ray opaque material 6. The tubes may, of course, beformed with any desired cross-section and size and further treated forend connections and the like in accordance with the particularapplications.

In use, the proximal end of the tube 1 is connected in any suitablewell-known manner to a ground. Thus any electrostatic charge which tendsto develop on the tube during use is automatically discharged to ground,maintaining a completely neutral tube condition, thereby essentiallyeliminating the hazardous conditions. Further, when exposed to an X-raybeam the location of the stripe appears distinctly to define thelocation, the precise location of the tube within the body cavity.

The present invention thus provides a simple and inexpensiveconstruction of a medical tube which is both radiographically opaque andconductive such that it can be employed in both surgical andnon-surgical procedures. The minimizing of the costs permitsconstruction as a throw-away tube.

I claim:
 1. The method of making a thermoplastic medicosurgical tubingwhich is radiographically opaque and conductive, comprising the steps ofincorporating with a flexible, waterproof thermoplastic material whichis non-conductive and which passes X-rays a mixture of a finely dividednon-conductive radiographic opaque material and a finely dividedradiographic transparent conductive material to form a thermoplasticcomposition, and forming a tubing of separate flexible, waterproofthermoplastic material which is non-conductive and which passes X-raysand of said thermoplastic composition with the thermoplastic compositionlocated as an integral narrow strip extending longitudinally throughoutthe length of the tubing.
 2. The method of claim 1 including the step ofsimultaneously extruding said thermoplastic composition with theseparate thermoplastic material, said separate thermoplastic materialbeing devoid of said mixture of said opaque and conductive material.